1. Field of the Invention
The invention relates to a network system for transporting audio signals among a plurality of nodes and an audio signal processor capable of being incorporated into the network system as one node.
2. Description of the Related Art
Conventionally, an audio network system has been known for transporting audio signals between a plurality of nodes, and is used in concerts, dramas, music production, private broadcasting, and so on. Known examples of such an audio network system include CobraNet™, and EtherSound™ as described in the following Documents 1 and 2.
Document 1: “CobraNet™”, [online], Balcom Co. [Retrieved on Mar. 21, 2006] Internet <URL: http://www.balcom.co.jp/cobranet.htm>
Document 2: Carl Conrad, “EtherSound™ in a studio environment”, [online], Digigram S. A., [Retrieved on Mar. 21, 2006] Internet <URL: http://www.ethersound.com/news/getnews.php?enews_key=101>
Known methods of transmitting digital data includes the method called SONET/SDH disclosed in the following Document 3.
SONET/SDH is the generic name of SONET (Synchronous Optical NETwork) and SDH (Synchronous Digital Hierarchy) and is a standard of the optical transmission technique realizing speed up of the line by hierarchically stacking and multiplexing low-speed lines. SONET and SDH can be considered as substantially the same standards though their details are different, and can also be mutually connected. SONET/SDH is a transmission method that is the base for construction of MAN (Metropolitan Area Network).
SONET/SDH is designed to construct a high-speed and highly reliable network utilizing the ability of the optical fiber. SONET/SDH includes various functions for operation and management, and is excellent in the backup function of responding to disturbance of the line. This function is called a protection (switch) function, and a ring protection is famous in which SONET/SDH is configured in a ring shape called SONET/SDH ring (simply referred to as a “SONET ring”).
Document 3: “SONET/SDH”, [online], Foundation for MultiMedia Communications, [Retrieved on Jun. 27, 2007] Internet <URL: http://www.fmmc.or.jp/fm/nwmg/keyword/fujitsu/sonet.htm>